1. Field of Invention
The invention relates to a signal exchange system, and more particularly to a signal exchange system with power supply capability and a transforming connector thereof.
2. Related Art
Power over Ethernet (POE) is a technique for providing an operating power to a network terminal device through a network line. In the prior arts, only a part of wires in the network line are used to transmit data and the other part of the wires are unused. The POE technique can use the unused part of wires to transmit power. When the POE technique is applied to the network-switching device, the network-switching device can transmit power to the terminal network device (not shown in the figures) through the network line. Therefore, some small power terminal network devices, such as the power is smaller than 12.95 W, can retrieve the required power from the network line, therefore, additional power line is unnecessary.
Referring to FIG. 1, a conventional signal exchange system 1 with the POE function includes a circuit board 10, a power source connector 11, a transformer 12, a network port 13 and an external power source equipment (PSE) 14. The power source connector 11, the transformer 12 and the network port 13 are soldered on the circuit board 10 and form a transmission path on the circuit board 10. The transmission path connects the power source connector 11, the transformer 12 and the network port 13 in sequence. The external PSE 14 includes a power source 141, a switch 142 and a PSE control circuit 143. A power line 15 is electrically connected to the PSE control circuit 143 and the power source connector 11.
The power source 141 outputs a power signal P of 48 VDC, which is transmitted to the network terminal device through the switch 142, the PSE control circuit 143, the power line 15, the connector 11, the transformer 12, the network port 13 and a network line coupling with the network port 13 in sequence. Thus, the power source 141 can provide the power to the terminal network device.
However, in the above mentioned configuration, the circuit board 10 must include an individual power source connector 11 to receive the power outputted from the PSE control circuit 143. In addition, the circuit board 10 must include an individual transformer 12 to convert the power signal P, such as a voltage signal. Therefore, the power source connector 11 and the transformer 12 will occupy a certain space of the circuit board 10 so that the signal exchange system 1 can be not miniaturized.
In addition, the voltage of the power signal P transmitted between the power source connector 11 and the transformer 12 is higher than that of the data signal transmitted in the circuit board 10. Therefore, when the power signal P is transmitted to the circuit board 10, the data signal with lower voltage will be interfered critically and the transmission quality thereof will be decreased. Accordingly, a circuit board including at least six layers is needed to be used in the conventional signal exchange system 1, so that the power signal and the data signal can be respectively transmitted in the different layers. The interference caused by the two signals in the circuit board may be decreased by the above mentioned method, but the circuit layout may become difficult and the cost to manufacture the signal exchange system 1 is increased due to the extra layers (at least six layers) of the circuit board.
Therefore, it is an important subject to provide a signal exchange system with power supply capability to improve the above-mentioned drawbacks.